因此他们组织了一场试验，以观察被允许自由择偶的斑胸草雀是否会比配偶由人工搭配的斑胸草雀生活的好些。

So they constructed an experiment to discover if birds allowed to pursue life with a chosen mate fared any better than those forced into an arranged union.

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另一组试验中，没有配偶的企鹅在陌生者旁仔细闻味的时间是花在亲戚身上的两倍。

In another, penguins without mates spent twice as long investigating unfamiliar penguins' scents than those belonging to their close relatives.

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